Numerical simulation and experiments of nano-second pulsed laser cleaning titanium alloy oxide film

Abstract

Nanosecond pulse laser cleaning is a highly promising cleaner technology. A finite element model (FEM) was established by introducing ablation heat flux. The surface temperature of oxide film first rises and then decreases, as well as the oxide film removal depth; both are completed within an extreme time (about 5 µm) during a single laser pulse loading. The oxide film removal depth increases in a step manner as the laser pulse numbers increase. The surface oxide film can be removed with a laser fluence of 3.82−6.37J/cm2. When the laser fluence is 1.27J/cm2, the surface temperature reaches the oxide film melting point, and the oxide film melts. The laser fluence accumulates severely, and the substrate is damaged with 8.92J/cm2. The laser cleaning experimental quantity is simplified by introducing the laser fluence and spot overlap rate as experimental variables. By analyzing the material's morphology before and after laser cleaning, the cleaning and damage thresholds of nanosecond laser cleaning titanium alloy oxide film were defined, and then the laser cleaning process window was also determined. The FEM results are consistent with the experiment results by comparing and analyzing. The FEM has important application prospects in laser cleaning titanium oxide film technology.